Agregar campo username a User entity y DTO

- Columna username (unique, nullable) en auth.users
- Campo username en CreateUserDto y UpdateUserDto

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tts/piper/espeak-ng-data/voices/!v/Jacky

@@ -0,0 +1,17 @@
+language variant
+name Jacky
+
+pitch  85 130
+
+formant 0 150 155 100
+formant 1 90 155 70
+formant 2 95 70 64
+formant 3 15 20 30
+formant 4 20 30 40
+formant 5 65 20 65
+formant 6 70 80 100
+formant 7 20 80 100
+formant 8 100 95 80
+voicing 135
+consonants 110
+